The broad-based index is riding high on just a few select winners – tech players Meta, Apple, Nvidia, Microsoft.

The S&P 500 crossed into a bull market after exiting its longest bear-market slump since the 1940s. Wall Street’s broad average gained 0.6% on Thursday, led higher by AI-focused companies, which make up about 15% of the index. In addition, Apple, which gained 1.5%, makes up nearly 10% of the $35tn index.

The benchmark average was in a bear market for 248 days before it topped 20% from its October low. While the gains are impressive in the context of current events like higher interest rates and inflation, investors need to thank the AI revolution that’s making all this possible.

The Nasdaq Composite and the Dow Jones also advanced, notching gains of 1% and 0.5%, respectively. What’s ahead, however, will likely inject more uncertainty in the markets over the next few trading days. The Federal Reserve’s meeting next week will wrap up with an interest rate decision on Wednesday.